The Enemy of My Enemy is a Potato
by Lucyndareads
Summary: The TARDIS malfunctions (again) and sends the Doctor to Aperture Science, where he quickly makes an enemy of the facility's resident AI and an ally of Chell. (Set during Portal 2). This is my first story on here! Probably going to be about 3-5 chapters.
1. Chapter 1

A Doctor Who/Portal 2 Crossover

The Doctor looked up with an big smile as the TARDIS roared to a stop. Anxious to discover where he had landed, he yanked his overcoat on and flung the exit doors open. He briefly glanced over his shoulder, surveyed the empty console room, and sighed gloomily. Shaking it off quickly, the excited Time Lord entered the outside world.

It wasn't "outside", though. In fact, it was downright claustrophobic. The walls were a tainted white, the floor was made up of some sort of metal panels. Harsh lights were everywhere, but they flickered constantly. The Doctor spotted areas where mould was beginning to grow, and as he took in all of this he surmised, "No one's been here in a long time."

As the words left his lips suddenly, a door beeped and slid open. A speaker crackled to life behind him. "Welcome to Aperture Science," piped up a cheery male voice, "Thank you for volunteering for testing. If you have not volunteered, thank you for allowing yourself to be forced into testing." Raising his eyebrows slightly, the Doctor stepped through the doorway.

The room he found himself in was newer, cleaner. The lights beamed steadily, and a sign glowed, showing a large 01 and a couple of diagrams. The Doctor studied them for a second, then grinned.

"Oh, it's a puzzle, that's brilliant!" He picked his way through the puzzle quite briskly, without difficulty. In fact, the moment he stepped through the exit door the speaker commended him. "Congratulations! You have completed the first test in record time. You have won .05 minutes of a break! In 50 years. Please move to the next test."

Now the Doctor was completely bemused, and suspicious. His finely tuned senses detected something wicked in the atmosphere. Stepping into the small, tubelike elevator, he resolved to find out the story behind this facility. But he wanted to try a few more tests first.

An hour and fifty tests later, the Doctor was bored. He pulled his sonic screwdriver out and began to probe one of the diagram screens. "Aaaaall righty, then! Let's see what this place is really about." As the screwdriver whirred, the screen flickered into a monitor displaying information about Aperture.

"Cave Johnson, hmm? I remember something about him…. oh, I see. So what year is it now? Wow, 2250. So this place _has _been abandoned for a while. But someone is still making sure this facility stays running…. and what happened?" He began to push the computer a bit more, but before he had the chance to see anything else-

"Who are you? What are you doing?" The voice was chilled and robotic. The Doctor whirled around to face what he assumed to be the lab's AI interface.

He grinned sheepishly, "Hello! I'm the Doctor. And I'm currently… erm…. hacking into your database, actually. Terribly sorry about that. I didn't realise this facility had an AI interface I could talk to. But this is lovely, much more sociable, don't you think?"

The yellow eye regarded him coldly. "Doctor?" it inquired, "Doctor who?"

"Oh, not important. Just the Doctor," he replied, "And do you have a name?"

After a long pause the interface replied, "GLaDOS."

"Very nice to meet you, GLaDOS."

"Are you the subject who has been breaking all the testing records?"

"Yep, that's me. Nice equipment, here, in fact it's quite spectacular."

"Thank you," GLaDOS coolly replied, "And congratulations. Your impressive test time has saved your life."

"Sorry, what?" frowned the Doctor.

"The penalty for hacking into Aperture is the death by neurotoxin," GLaDOS gleefully informed him. "But I can't lose your testing skills. However, I am taking away your sonic device. And throwing it into the incinerator. That's cheating. Now if you will excuse me, I must attend to another… difficult… testing subject." Before the Doctor could protest, a metal arm snatched the device from him. And suddenly GLaDOS was gone, and the Doctor was alone.

"I'm going to want that back, you know!" he shouted. Something was horribly wrong here. And if that horrible AI had another person trapped here, he had to help wouldn't be that challenging. Just one trip in the TARDIS and-

"Oh dear…" the Doctor sighed as he realised he was hopelessly lost. This was going to be quite challenging.


	2. Chapter 2

About an hour later, he was ready to give up. The facility was huge, and more like a labyrinth than a laboratory. He was just getting desperate enough to try and talk to one of those childlike robot guards, when there suddenly was a tremendous commotion. Lights flickered, things fell, and he heard an odd sort of screaming. Picking up the origin of the noise, he began running, bobbing and weaving as debris fell in his way. Suddenly, the commotion stopped. The facility began fixing itself, in a brighter way. The Doctor stopped as he realised he had lost the trail. "Oh, not lost _again!" _

He began ambling aimlessly. Not very long after, though, he began to hear more noise, this time it sounded like a man was shouting. The Doctor proceeded to run towards the source, which was now emitting maniacal laughter. Rushing into the room where he was positive it had come from, the Doctor saw…

Well, at first he thought it was GLaDOS, but the voice was wrong. And so was the shape of it. He surmised that it was a different AI. And judging by the way it was acting, it was no nicer than its predecessor.

"Who's there?" it called out, "Hello?" The Doctor found himself fixed in an electric blue gaze.

"Um… hi. Are you… an assistant of GLaDOS?" Immediately he knew that this was not the right thing to say.

"Me? An assistant? Of _HERS?! _I am FAR SUPERIOR to that rusty bucket of bolts! _And_ that girl! And you!"

"I'm sorry, I didn't mean to offend-" began the Doctor.

"Sorry won't cut it, smarty-pants!" the AI barked, "Down the chute with you and tell both of them I said hi! Wait… no. Don't want you to meet up with them. Different chute, yeah, that's brilliant. Have a nice fall!"

He fell for a long time. As the wind brushed past him he realised that this could actually be it. This fall would certainly kill him. Of course he would regenerate, but there were many he'd like to say good-bye too…. and how would he find his way out of this hole? As he thought this, the Doctor's world suddenly turned blue.

And he bounced. Landing somehow on his feet, he stumbled forward and tried to regain balance. "Oh, I wouldn't recommend that to anyone," he mumbled. Turning, he examined the blue gel that had saved his tenth life. "Well that's certainly my lucky colour," he chuckled as he put a finger to it, then to his lips. "Lunar rocks! Harmless, but powerful. Amazing usage! This gel won't be in use until at least ten years later. Whoever designed this place was brilliant! Mad, of course, but ferociously brilliant. I mean…" His voice trailed off as he sensed a presence in the room. But for the first time since he had arrived at Aperture, the presence didn't feel hostile.

"Hello?" he called gently. No one replied, so he tried again. "I promise, I'm not going to hurt you!"

With hesitant steps, a young woman made her way out of the shadows. She was on the shorter side, with tan skin and dark hair pulled into a messy ponytail. Her eyes were green in colour. She wore an orange jumpsuit undone to her hips and a white tank top, both with Aperture's logo on them. Her boots looked extremely high tech and robotic. She squinted at him, saying nothing.

The Doctor smiled at her, "Hello!" he cried, wagging his fingers, "I'm the Doctor, nice to meet you. Blimey, I'm making a lot of introductions today. And you are?"

She did not answer. Instead, her eyes widened as she stared at him. Stretching out her left hand, she touched the Doctor's right hand gingerly. "Are you ok?" asked the Doctor gently. She did not respond. The Doctor recognised the look on her face however, and he realised, "I'm the first non-robot you've seen in a long time." From the way she looked at him, he knew he was right.

"Well, I'm sorry for what you've gone through. But it ends now, you understand? I'm going to get you out of here. I swear it." She nodded, and made a face that was clearly an attempt to stop tears brimming in her eyes. Taking a chance, the Doctor strode forward and hugged her tightly. After a second, she hugged back. "Can you tell me your name?" She shook her head sadly. "Can you talk?"

"Of course she can't talk, you moron. She's too simple to talk." This familiar, cruel voice came from the corner of the room.

The Doctor jumped. "GLaDOS? Where are you?" Turning to the girl he said, "Is she-" but the girl merely rolled her eyes and shook her head. Stepping back, she pointed to what appeared to be a potato in the corner.

"What are you looking at?" demanded the potato, who was clearly GLaDOS. The Doctor looked at her, than back to the girl, and burst out laughing. The girl grinned widely.

"Wha… what happened to you?" the Doctor sputtered as he attempted to stop laughing hysterically. If potatoes could look offended, this one did.

"That _idiot _Wheatley convinced that treacherous girl to plot against me." The girl glared at GLaDOS, making it very clear that she had needed no convincing. "Her name is Chell, by the way, and I still have no idea why she can't talk."

"Nice to meet you, Chell," he said softly.

"Yes, anyway, the problem with having Wheatley in charge is that he's a moron. No, really. He was built to be one. He can't run this facility properly like I can. He's going to blow it up. We have to stop him."

"What, and put you back in charge?" asked the Doctor sharply. "I've got a feeling about how you've been 'running this facility', GLaDOS. Poor Chell must know firsthand. We're not helping you."

"Oh dear, I'm afraid you have no choice. I know this facility quite well, including the location of both your sonic device and your transport. I am your only hope of us getting out of here."

The Doctor regarded her shrewdly. "Let me talk this over with Chell," he decided. He entered the next room, Chell in tow. Turning suddenly, he put his hands on her shoulders. "Look, Chell, GLaDOS is right. She'll be a good help to us finding our way. I realise we can't trust her, and if I can get back my sonic screwdriver, I can see if she can be reprogrammed. But I'm not doing all that without your consent. I imagine she's put you through hell here. Are you comfortable with my plan?"

Chell looked at him for a couple seconds. She frowned and shrugged, a question in her eyes. "You don't know a thing about me," realised the Doctor, "and I'll bet you trusted that Wheatley fellow too. I have a way of communicating telepathically. Please trust me enough to try and communicate with you?" He reached his hands toward her face. Chell gaped at him, then shrugged again, her expression clearly stating: _What the hell. I've got nothing to lose. _ For a few minutes the Doctor held his hands to her temples. Chell's eyes widened as she took in the information. "Oh, Chell, you really have had quite a life in here. And something seems to have paralysed your vocal cords at an early age. You really are a star, for staying so strong. Do you think you have enough information about me?"


End file.
